Bacterial developmental checkpoint that directly monitors cell surface morphogenesis

Bacterial cell surface nanoenvironment requires a specialized chaperone to activate a peptidoglycan biosynthetic enzyme

“…4F, lane 3). When coat assembly is impaired by an ATPase-defective SpoIVA (SpoIVA B* ) that does not polymerize, we observed an increase in the accumulation of Park’s nucleotide, similar to what we observed previously (28). This accumulation was exacerbated in the absence of SpoVK but was corrected in the presence of SpoVK A5V (Fig.…”

“…4D, lanes 6-7). We conclude that the LysM domain of SpoVID, which is unmasked when the spore coat fails to assemble properly (28), is simultaneously required for proper localization of SpoVK and negatively influences the stability of SpoVK.…”

“…This genetic selection yielded a loss-of-function mutation in the spoVID gene (25). We previously presented evidence that SpoVID participates in a checkpoint that monitors coat assembly and, upon sensing a coat assembly defect, would arrest cortex assembly by sequestering the peptidoglycan intermediate lipid II via a C-terminal LysM domain that is unmasked only when the coat mis-assembles (28). To identify additional factors involved in the communication between coat assembly and cortex formation, we used a similar genetic strategy to isolate additional suppressor mutations that would correct the sporulation defect of spoIVA T* , but this time we used a strain harboring two copies of spoVID to avoid isolating loss-of-function mutations in spoVID .…”

“…Trypsin digestion of these bands followed by mass spectrometry revealed, as expected, that the ∼36 kDa band was SpoVK B* -FLAG. The ∼65 kDa band was identified as SpoVID, a factor that we recently identified as participating in a sporulation checkpoint that monitors spore coat assembly (28). Immunoblotting the fractions using anti-SpoVID antibodies confirmed that SpoVID specifically co-purified with SpoVK B* -FLAG and the gain-of-function SpoVK B*, A5V -FLAG, but not SpoVK B* -His 6 (Fig.…”

“…However, if SpoIVA mis-assembles, the C-terminus of SpoVID is liberated, thereby exposing the LysM domain which binds to and sequesters the lipid II precursor in the mother cell cytosol, thereby blocking cortex assembly. Although SpoVID molecules (and therefore LysM domains) vastly outnumber the estimated number of lipid II molecules at any given time (28), it was not clear how the checkpoint could remain functional in the face of additional lipid II synthesis that may overwhelm the lipid II sequestration capacity of SpoVID.…”